Small Intestine Bacterial Overgrowth

While it is well established that the large intestine (colon) is highly colonized with a diverse range of microorganisms, the small intestine should be a relatively sterile environment. Small Intestine Bacterial Overgrowth (SIBO) occurs when there is too much bacteria (>10^3 organisms/mL) residing in the small intestine producing a wide range of effects on the body.

SIBO often presents similarly to IBS-D/C, however, it is a challenging condition to diagnose and therefore its incidence is unknown.

There are many reasons why SIBO may occur, but the primary cause of SIBO is motility abnormalities. What this means is that the nerves responsible for movement through the digestive tract are impaired. Celiac disease, structural issues, head injury, food poisoning, organ dysfunction, and IBD are just some of the contributors that damage the digestive tract and nervous system functioning, increasing the risk of SIBO.